Initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the schematic diagram the component pin pads were laid out on the mylar and then traces were routed to connect the pads. If you have many questions of PCB Design, please come here!

With constant development of information technology, electronic products are becoming increasingly complicated in terms of their functions, categories and structures, driving PCB design towards direction of multiple layers and high density. As a result, much attention has to be paid on EMC (Electromagnetic Compatibility) of PCB design since EMC design of PCB not only ensures normal and stable working of all the circuits on board so that they won't be mutually interfered with each other but also effectively decreases radiation transmission and conducted emission of PCB in order to stop circuits from being interfered by external radiation and conduction. Interference is the foremost enemy of EMC. But, engineers, you should stop worrying from this article on.